The present invention relates to an individual protective equipment for use in a hostile environment, particularly in an atmosphere which contains harmful or corrosive products, comprising a closed suit provided with a built-in respiratory gas supply and means for ventilating the closed suit.
Equipments of that type are known which include a closed suit comprising a flexible gas-tight garment and a helmet having a transparent visor, which is connectable to a gas supply consisting of a cylinder for delivering pressurized breathing gas.
During work in such an atmosphere, the protective equipment should deliver breathing gas in appropriate quantity and quality and also ventilate the body surface for drawing off heat and avoiding moisture condensation.
Typically gas from the cylinder is fed to an ejector which draws air from the suit and circulates it for ventilation purpose. The atmosphere breathed by the wearer of the protective suit consists of a mixture of delivered breathing gas and of gas from the inside of the suit. Gas delivery from the cylinder is balanced by exit through valves on the suit.
Such known equipments have drawbacks. The ventilation circuit may be considered as open, which results in a waste of breathing gas. There is dilution of the exhalated gas within the whole atmosphere within the suit and the carbon dioxide content rapidly increases and may reach a dangerous value.
As a consequence such equipments are self-sustaining for a short time only, since the volume and weight of the cylinders storing the pressurized gas used for breathing and ventilation should remain within acceptable limits.
The mere substitution of a pressurized breathing gas bottle fails with a liquefied gas supply to cure most of the above-identified drawbacks.